Cool, cool, cool info diesl_dad...
Thanks for sharing all that. Nice to have people who will follow up with all the details of their creative inventions for others to emulate if they wish.
The thing I really like about what you did is as you describe (accurately) in your initial post with the words "solid" and "professional." So many other products to do the same thing seem more like they should be described as "make do" contraptions.
One more question on behalf of those concerned with weight issues, though (I personally don't have many of those kinds of concerns at my cycling level, though). Do you happen to have a scale that can give you an accurate weight on the mount? I'll bet quite a few of the riders looking at your invention might want to know that.
Really glad the fruits of your labor have come out with such a tasty result. Your time, effort, and creativity certainly seem to have been rewarded.